U.S. Pat. No. 5,593,425 to Bonutti et al. discloses a heat-bondable, expandable surgical anchor for fastening soft tissue to a blind hole in a bone. One embodiment of the device, shown in FIGS. 9A-9D of Bonutti et al., includes an expandable anchor portion, a suture extending from the anchor, and a heat bondable fastener portion which is bonded to the suture to lock the anchor in place. Another embodiment, shown in FIGS. 11A-11C, is a rivet fastener including a sleeve and a headed mandrel which extend into a blind hole in a bone through the tissue to be anchored. The mandrel is pulled through the sleeve, which is held stationary, so that the head spreads the rear portion of the sleeve to lock it in place in the bone. The end of the mandrel is cut off and heat bonded to fix the anchor in place.
The Bonutti et al. devices are deployable in a blind hole in a bone but require a final heat bonding step to lock the devices in place. It would be advantageous to provide an expandable soft tissue anchoring device which is fully deployable in a single step.